Sound amplifier



FIG. 1 is a perspective view of a sound amplifier;

FIG. 2 is a front view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a left side view thereof.

The broken lines shown in the views are for illustrative purpose only and form no part of claimed design. 

The ornamental design for a sound amplifier, as shown and described. 